Question: In math class, the girl to boy ratio is $2$ to $10$. If there are a total of $36$ students, how many boys are there?
Solution: A ratio of $2$ girls to $10$ boys means that a set of $12$ students will have $2$ girls and $10$ boys. A class of $36$ students has $3$ sets of $12$ students. Because we know that there are $10$ boys in each set of $12$ students, the class must have $3$ groups of $10$ boys each. There is a total of $30$ boys in math class.